﻿#u {
    width:600px;
    height: 250px;
    background-color: red;
    float: left;
    z-index:3;
}
#ucen{
    width:50%;
    height:250px;
    background-color:red;;
    float:right;
   
    z-index:4;
}
#ule {
    width: 50%;
    height: 250px;
    background-color: blue;
    float: left;
    z-index: 4;
}
#uri {
    width:300px;
    height: 250px;
    background-color: yellow;
    margin-left: 4px;
    float: right;
    z-index: 4;
}

#dcen{
    width: 402px;
    height: 250px;
    background-color:aliceblue;
    margin-top:250px;
}